How do you add a Opera thumbnail for your site?

After the release of Barracuda Opera uses the <link rel=”icon”> or <link rel="apple-touch-icon"> meta in the site's header to find the logo, but it will only show in Opera if the attached image is wider than 114px.

In stackoverflow's case the code looks like this:-

<link rel="apple-touch-icon" href="http://cdn.sstatic.net/stackoverflow/img/apple-touch-icon.png">

Which links to a 158 x 158px icon image

You can also use (dynamic) HTML to show the latest article headlines, images or comments. See Make your site shine in Speed Dial for details.